Wheel immobilization devices are employed in a variety of situations, most commonly being the wheel chock. Wheel chocks provide an easy and inexpensive way to ensure that a vehicle will remain at rest if a parking brake should fail. Often chocks will have a triangular or rectangular cross section, the former being the preferred shape because it approximates the shape of a tire and thus provides a greater assurance of immobility. Wheel chocks are frequently used to restrain large trucks, mobile support equipment, or in the case of the present invention, aircraft, aircraft tugs, luggage tugs, aircraft stairs, fuel trucks and similar ground support equipment.
It is common practice at most airports to provide chocks and/or tie-down means at aircraft parking and staging areas to prevent aircraft from rolling due to uneven pavement surfaces or wind impingements. More specifically, chocks prevent horizontal motion, while tie-downs generally prevent vertical motion, for example lift generated by high ground winds. Thus, chocks and tie downs provide sufficient immobilization for small aircraft. Larger aircraft generally do not require tie downs since ground winds have a reduced effect thereon, due to their increased weight. Tie-downs also may be capable of providing sufficient rolling impedance for smaller aircraft if chocks are not available.
After the Sep. 11, 2001 terrorist attacks on the United States, it became painfully evident that America's aircraft and airports are in need of greater security measures. One area that requires more security are airports that serve private pilots and business jets. Even though security has been increased as a result of the terrorist attacks, there are still gaping holes that may allow a terrorist with the proper skills to steal an aircraft and reek havoc. Moreover, many small airports are not continuously monitored and are not protected by fences or walls, nor do they have hangars for aircraft housing. A would-be terrorist could easily gain access to the aircraft parking area, remove the chocks and tie-down chains, gain access to an aircraft, “hot-wire” the ignition, and take off. Since many single engine aircraft are light weight and have low wing loading, a runway take off may not be necessary, such that a taxiway would suffice to enable the aircraft to become airborne. Thus, an aircraft could be in the air before ground or tower controllers realize that the aircraft had been stolen. Even though one small single-engine aircraft may not do much damage, many coordinated aircraft would do great damage to a building, sports venue, or other structure.
An aircraft may be locked via the tie-down means. Chain or cable tie-downs, which interconnect wing attachment points to the ground, may be integrated with locks in order to prevent unauthorized movement of an aircraft. Unfortunately, many of these types of tie-downs are prone to rust and are easily cut. Alternatively, the attachment hardware on the aircraft could be removed. Finally, many small airports employ rope tie-downs which provide no protection against theft.
Propeller locks are another means of preventing unauthorized use of an aircraft. However, propeller locks may be undesirable to employ because generally they are heavy, cumbersome, difficult to install and remove, and are apt to damage the propeller during installation and removal. In addition, propeller locks only prevent movement of the propeller, the wheels of an aircraft utilizing such a lock may be moved, wherein the aircraft may be stolen. Finally, propeller locks are useless in conjunction with jet aircraft.
There are many wheel locking devices in the prior art. For example, United Kingdom patent No. 2,112,725 to Milner et al. (hereinafter “Milner”) describes a wheel locking device that comprises a forward chock and a rear chock that are slidingly interconnected. The drawback of Milner is that an inner chock member which is located adjacent to the internal surface of the wheel, will possibly interface with internal components of the vehicle wheel and interconnection of the inner chock members is difficult.
In addition, U.S. Pat. No. 3,695,071 to West (hereinafter “West”) and U.S. Pat. No. 5,427,210 to Willaford (hereinafter “Willaford”) each discloses a wheel interconnection system that includes inner wheel contact members that prevent transverse disengagement of the chock. However, one drawback of West is that the device must be physically interconnected to the wheel, which is often difficult to perform, especially when the parking area is cold, snowy and/or wet.
U.S. Pat. No. D385,526 to Hinkle (hereinafter “Hinkle”) shows a wheel locking device comprising two chocks that are interconnected with a sliding member. The drawback of Hinkle is that it does not include a member that engages the inner surface of the wheel, so the interconnected system may be easy moved transversely and disengaged from the wheel.
The foregoing is mainly concerned with small private aircraft, but theft can foreseeably occur with respect to larger aircraft or other types of vehicles, although the sophistication of a thief or terrorist may necessarily be greater. Theft of business or jumbo jets may foreseeably occur, which are capable of causing great damage. Further, as was the case in the Oklahoma City bombing, trucks have been used in the past as weapons of terror. Finally, wheel immobilization devices are useful in immobilizing aircraft ground support equipment. More specifically, aircraft tugs, baggage tugs, fuel trucks, aircraft stairs, food trucks, etc. are used in close proximity to aircraft at many airports. These vehicles could be used to damage aircraft and other equipment, to injure ground support personnel, and to damage property in or around the aircraft servicing areas of airports. In addition, fuel trucks may be stolen and used for terrorist purposes.
Thus, there is a long felt need in the field of wheel immobilization to provide an apparatus that is capable of locking interconnection with a vehicle to prevent theft while ensuring vehicle immobility. More specifically, it has been an urgent need to provide a means to secure parked aircraft and aircraft ground support equipment so that they do not become tools for terrorists, vandals or thieves. The following disclosure describes a locking chock that is adapted to immobilize various types of aircraft ground support equipment.